DAVID MACKINNON

..The best balance of Type I error and statistical power across all cases is the test of the joint significance of the two effects comprising the intervening variable effect...

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..Although the statistical estimation of effects and standard errors is the same, there are important conceptual differences among the three types of effects...

..To describe effects of 2 worksite health promotion programs for firefighters, both immediate outcomes and the long-term consequences for 4 years following the interventions...

..Often the addition of these measures to research projects costs very little, but offers tremendous potential to yield detailed information critical to the advancement of theory and practice in health psychology...

..This article provides an overview of statistical mediation analysis methods in the evaluation of public health dentistry interventions...

..Several examples are used to illustrate the PRODCLIN program. The PRODCLIN programs in rich text format may be downloaded from www.psychonomic.org/archive...

..Statistical methods to assess mediation and modern comprehensive approaches are described. Future directions for mediation analysis are discussed...

..More complicated dismantling and constructive designs are described and illustrated based on current findings from tobacco research. Mediation analysis for categorical outcomes and more complicated statistical methods are outlined...

..Implications of these findings for understanding the development of mental health problems following parental bereavement are discussed...

..These findings, combined with those from qualitative research and the second-year student data, will help to illuminate the impact of Project MYTRI on participating youth...

..Finally, we presented a numerical example and a SAS MACRO that calculates the CIs for the effect size measures...

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..The present study extended previous findings by evaluating diet-specific and activity-specific social-ecological resources as possible mediators of intervention effects over a 2-year period...

..The article concludes with a description of recent developments in mediation analysis and suggestions for the use of mediation for future work in psychosomatic medicine research...

..Results are discussed in terms of the potential synergy between ECN and social influence training in tobacco preventive intervention development among youth of Latin descent...

..National data sets from Great Britain (the British Births Cohort Study [BCS]) and the United States (National Longitudinal Study of Youth [NLSY]) are used to explore this pattern of effects...

..The experimental manipulation of mediators and the demonstrated mediation effects support the conclusion that social-ecological resources can contribute to improvements in healthful lifestyles for women with type 2 diabetes...

..Both of these interactions were beneficial in that they increased the effectiveness of the program for participants lower in knowledge and higher in intentions at baseline...

..Analyses demonstrate mediation effects primarily for children who began the program with poorer scores on discipline, mother-child relationship quality, and externalizing problems...

..The increased availability of statistical software has contributed greatly to the use of new methods in prevention research. It is likely that the Internet will continue to stimulate the development and application of new methods...

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..Methodologically, results suggest that the ANCOVA method should be employed with caution, and that the change score method is a viable approach to confirming results from the ANCOVA method...

..An empirical example is then presented to illustrate these plots. Sample code for creating plots of the mediated effect in R and SAS is also included, and may be downloaded from www.psychonomic.org/archive...

..Possible effects of interest in the model are explained, as are statistical methods to assess these effects. The methods are further illustrated in a hypothetical prevention program example...

..Implications for the estimation of mediated moderation effects in experimental and nonexperimental research are discussed...

..Practical strategies for reducing model complexity, checking model fit, and handling missing data are discussed using six randomized field trials to show how these methods may be used across trials randomized at different levels...

..To assess the deterrent effect of mandatory, random drug testing among high school (HS) athletes in a controlled setting...

..Study 5 will disseminate new information about mediation analysis including the development of a mediation analysis working group and additions to our mediation analysis website. ..

..In addition, more common statistical methods will be used to extract the maximum information from these data The findings in one project site will be cross-validated in the other site. ..

..The overall purpose of the grant is to use advanced as well as more common statistical methods to extract the maximum important information from these data and publish the results. ..

..As part of Study 7, we will increase the use of mediation methods by the establishment of a consultation service and an interactive computer program to teach researchers how to conduct mediation analysis. ..

..Mediation analysis provides information on how and why prevention and treatments are successful. Mediation analysis can improve prevention and treatment so that they have greater effects and even cost less. ..